This invention relates to the field of treating textile fabrics with fabric finishing agents, and more particularly, to foamable compositions for applying fabric finishing agents to textile products.
Conventionally, treatment of textile fabrics with finishing agents, e.g., coloring agents or dyes, resins, and the like, has involved a procedure wherein the finishing agent is either dissolved or dispersed in a suitable liquid medium, such as an aqueous or organic liquid, and then the mixture of the finishing agent and liquid medium are applied to the fabric. Thereafter, the carrier is removed from the fabric, usually by evaporation with or without heat. It is further conventional to use small amounts of the finishing agent, relative to the amount of liquid medium in order to conserve the amount of the finishing agent used. This produces relatively large amounts of liquid medium which must be removed from the fabric. Consequently, a substantial amount of the cost incurred in such processes resides in the liquid medium removal step.
Such liquid media present a further problem in that after removal, the liquid must either be disposed of or recovered for re-use. In the case of an aqueous treatment system wherein the liquid media is water, the water is normally disposed of as waste. In recent years, the environmental problems associated with the disposal of the water and residual finishing agents therein have become increasingly prevalent.
With respect to organic solvents as the liquid medium, it is normally desirable to recover them because of their relatively high cost. Recovery systems for this procedure add to the expense of the overall treatment process. Moreover, disposal of the solvent, if it is not recovered, may cause environmental contamination.
The foregoing problems become even more pronounced when treating textile fabrics which are highly absorbent. Thus, for example, when it is desired to treat or finish pile fabrics, e.g., carpeting, sliver knit fabrics, and the like, the fabrics have a tendency to absorb great quantities of the water or organic solvent, thus making the liquid removal step even more difficult and expensive. Additionally, because of the relatively large absorption of the liquid, the weight of the wet fabric which is being handled increases significantly.
In the co-pending application of R. S. Gregorian and C. G. Namboodri, Ser. No. 584,389, filed June 6, 1975 and now U.S. Pat. No. 4,118,526, there is described a novel process for the application of fabric finishing agents to textile fabrics which substantially reduces the large amount of liquid medium utilized in conventional processes. The amount of finishing agent required to produce the desired finishing effect on the fabric, is incorporated in a foamable composition capable of forming a stable foam having a blow ratio in the range of from about 2:1 to about 20:1. The composition is converted to a foam and coated onto the fabric and is thereafter compressed, padded and/or vacuumed to achieve penetration of the foam through the fabric. The so-treated fabric is then dried and, if necessary, cured or fixed in a conventional manner.
Although the process of the above-described application represents a significant advance in the textile treatment arts, further improvement may be achieved, such as in the nature of the particular composition to be used. For instance as was the case with liquid medium systems, the use of excess carrier medium is undesirable. Thus, in a foamable composition, usage of excess foaming agent results in an additional cost factor and may have adverse effects on finish durability. Likewise, further improvement may be achieved in the control of the foaming step and in the desire to reduce the cost of shipping, storage and the like necessarily associated with foamable compositions which typically contain large amounts of water or other liquid medium.